The Doctor's interaction with the Dalek was originally written to be just mocking and flippant. Christopher Eccleston decided to pour in incredible amounts of rage and pain as well. Robert Shearman was briefly miffed, then delighted once he realized how well it worked.
Robert Shearman had to write a second version of the script because it was not initially known if the new series could obtain the rights to use the Daleks from Terry Nation's estate, so he had to create an alternate alien race that would have been used had the Daleks not been available. The alternate monster was a spheroid creature akin to a sadistic child which was actually a mutated version of humanity from the end of time. Although this alternate concept was shelved, it would later be used for the Toclafane in the series 3 finale, The Sound of Drums (2007)/Last of the Time Lords (2007).
Behind and to the left of the TARDIS is a display holding an Xenomorph egg from the ALIEN series.
Bad Wolf Reference: As Van Statten's helicopter lands, we hear the announcement "Bad Wolf One descending".